The final significant hurdle for a blockbuster four-team trade that would send Carmelo Anthony(notes) to the New Jersey Nets hinges on the All-Star forward’s willingness to agree to a contract extension with the Nets, two front-office executives involved in the deal told Yahoo! Sports.Anthony is unhappy with the Nuggets' instability.

The Denver Nuggets and New Jersey are having ongoing discussions centered on No. 3 overall pick Derrick Favors(notes) and a protected 2012 first-round pick the Nets received from the Golden State Warriors going back to the Nuggets. The proposed trade also would involve the Utah Jazz and Charlotte Bobcats. Under the proposal, league sources said the Nets would also send point guard Devin Harris to the Bobcats, who would move forward Boris Diaw to the Jazz, who send forward Andrei Kirilenko to the Nuggets to complete what one front-office source described as a “very complicated” deal. The Nets also would receive point guard D.J. Augustin from the Bobcats.

One league executive said the Nets believe they’re “getting there” on a trade for Anthony.

Anthony still has heart set on the New York Knicks, but a case is being made to him the Nets are a compromise he’ll have to accept to get his $65 million extension and get into the metropolitan N.Y. market. The Nets won’t agree to a deal for Anthony without him first agreeing to an extension.

Anthony also prefers a trade to the Chicago Bulls, but Denver refuses to do a deal with the Bulls that doesn’t include center Joakim Noah(notes), and so far Bulls officials have refused to put him into any deal.

The Bobcats are ready to do their part of the deal because they want a starting point guard. Larry Brown had been hesitant to trade Diaw; his objections helped kill a proposed trade of Diaw to Toronto for point guard Jose Calderon this summer. However, with Tyrus Thomas re-signed to a $40 million extension, Brown is now inclined to part with Diaw to bring back Harris, an upgrade over Augustin.

The Nets want to get a deal done before Anthony reports to training camp in Denver next week because league officials think the Nuggets will start working to convince him to stay.

Anthony has refused to sign a three-year, $65 million extension with the Nuggets and has made it clear to team officials he’s not comfortable with the franchise’s stability. There’s unrest within the organization, where George Karl’s top assistant, Tim Grgurich, has left, league sources said. Grgurich has told friends he’s angry about the franchise’s refusal to retain former general manager Mark Warkentien. Karl is now without his two most trusted confidants in the organization, Warkentien and Grgurich.

Forward Kenyon Martin(notes) and guards J.R. Smith(notes) and Arron Afflalo(notes) will be free agents after this season and center Nene could join them if he opts out of the final year of his contract. Point guard Chauncey Billups(notes) also could hit the market because the Nuggets are obligated to pay only $3.7 million of his $14.2 million salary for 2011-12 if he’s waived at the end of the season.

With so much uncertainty surrounding the Nuggets, Anthony would like to be traded before the season starts.

Anthony is a way better player than Favors probably will ever be. I am not too fond of favors (3rd in what was believed to be a very weak daft class). Nets would be a shooting guard away of becoming a playoff team and beyond.